I am running Firefox 84.0.2 on a Macbook Pro running Catalina 10.15.7. Since the new version of Firefox loaded on January 6, I have been having problems with how email from several vendors displays. If I call up Hotmail, for example, the page appears in teeny tiny type, so small that I have to pull the computer close to my face to read. And if I enlarge the page in order to read the left-most column, I can then only see the left-most column on my screen. I have to then scroll far to the right to find the actual message itself. I have tried the various "Display" options, but none of them have fixed this problem. I switched over to Chrome as a test, and Hotmail is displaying normally there. So I conclude that there is some incompatibility between Firefox 84.0.2 and Catalina 10.15.7. Any advice would be most welcome! Thanks!